Safety ski binding

ABSTRACT

Safety ski binding comprising a movable plate adapted to pivot laterally on the ski and to receive the sole of a ski boot, a front jaw pivotally mounted on the front end of said movable plate about a pivot pin extending at right angles thereto, said jaw being adapted to be engaged by the toe end of the ski boot, and a resilient return device mounted on the ski ahead of said movable plate and adapted to urge said movable plate to its normal position when it is pivotally moved away therefrom. Said movable plate held against any longitudinal movement can only pivot about a fixed perpendicular axis and said return device acts upon the front jaw in such a manner that said front jaw is held in its normal position in relation to said movable plate when said movable plate is pivoted, but it is released therefrom only when the pivotal movement of said plate exceeds a predetermined angle.

United States Patent Rey] [ Mar. 7, 1972 [54] SAFETY SKI BINDING JeanJoseph Alfred Beyl, Boulevard Victor-Hugo, Nevers (Nievre), France [22]Filed: Nov. 21, 1969 [21] Appl. No.: 878,864

[72] Inventor:

Primary Examiner-Benjamin Hersh Assistant Examiner-Robert R. SongAttorney-Harry C. Bierman, Jordan B. Bierman and Bierman & Bierman [57]ABSTRACT Safety ski binding comprising a movable plate adapted to pivotlaterally on the ski and to receive the sole of a ski boot, a front jawpivotally mounted on the front end of said movable plate about a pivotpin extending at right angles thereto, said jaw being adapted to beengaged by the toe end of the ski boot, and a resilient return devicemounted on the ski ahead of said movable plate and adapted to urge saidmovable plate to its normal position when it is pivotally moved awaytherefrom. Said movable plate held against any longitudinal movement canonly pivot about a fixed perpendicular axis and said retum device actsupon the front jaw in such a manner that said front jaw is held in itsnormal position in relation to said movable plate when said movableplate is pivoted, but it is released therefrom only when the pivotalmovement of said plate exceeds a predetermined angle.

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SAFETY SKI BINDING This invention relates to a safety ski binding of thetype described in the applicant's French Pat. No. 1,271,671.

This safety ski binding comprises a movable plate adapted to support theski boot to be retained in the normal skiing position. This retainingaction is produced by means of a jaw pivotally mounted at the front endof this plate about a perpendicular pivot pin carried by this plate,this jaw being adapted to be engaged by the toe end of the ski boot.

On the other hand, a resilient return device is provided on the ski,ahead of said movable plate, for constantly urging this plate to itsnormal position and return it to this position when it has been movedaway therefrom by pivoting to one or the other side. The function ofthis resilient return device is to automatically restore the movableplate and the ski boot to their normal positions after they have pivotedto one or the other side as a consequence of a momentary torque exertedthereon. However, it is clear that the ski boot is released completelywhen a lasting and heavier torque is exerted thereon.

In the ski binding described in the aforesaid French Pat. No.

5 1,271,671, the resilient return device is connected to the movableplate by means of a pivot pin secured at right angles to the front endof said plate. This plate carries another perpendicular pivot pin aboutwhich the front jaw retaining the toe end of the boot is adapted topivot freely. Moreover, the rear end of said movable plate is soattached to thetop of the ski that is can move not only sidewise in oneor the other direction but also forwards.

However, the operation of this combined device is subordinate to theprovision of means for holding the heel portion of the ski boot on theski, these means consisting for example of a heel holddown deviceadapted to exert a relatively strong forward thrust on the ski boot, inorder to keep its toe end engaged in said front jaw. On the other hand,this relatively high thrust is likely to interfere with the properoperation of the ski binding as a whole. In fact, when the aforesaidmovable plate pivots sidewise, the resilient return device pulls itslightly forwards together with the front jaw and the boot. Under theseconditions, to restore the assembly to its normal position the returndevice must be capable of pushing said movable plate backwards, togetherwith the front jaw and the boot, by overcoming the thrust exerted by theheel holddown device. But this is obviously not possible if the thrustis relatively high.

Now this forward thrust is also produced when the ski bends more or lessas a consequence of its passage on ground depressrons.

For all the above-stated reasons, in many cases this ski binding cannotwarrant the automatic return of the ski boot to its normal positionafter it has pivoted laterally in one or the other direction with themovable plate, as a consequence of a momentary torque. Besides, it maybe noted that in the ski binding according to the above-mentioned FrenchPat. No. 1,271,671, the front jaw is mounted for free pivotal movementon the movable plate. Under these conditions, the boot will be releasedprematurely after said movable plate has pivoted through a relativelysmall angle.

Now exhaustive research work carried out in this field lead to theconclusion that for obtaining a highly reliable degree of safety aresilient ski binding must permit a relatively long release strokebefore the boot is released completely. This requirement mustcompulsorily be met if it is desired to constantly return the ski bootto its normal position without prematurely releasing the boot.

Therefore, it is the object of this invention to provide a ski bindingof the same general type as described hereinabove but The present skibinding is characterized essentially in that the movable plate adaptedto support the boot sole is pivotally mounted on the ski about a fixedpivot pin extending at right angles thereto, thus preventing anymovement thereof in the longitudinal direction, the resilient returndevice being on the other hand adapted to act upon the front jaw carriedby said plate in such a manner that this jaw kept in its normal positionin relation to said plate when the latter is caused to pivot, isreleased therefrom only in case its pivotal movement exceeds apredetermined angular amplitude.

According to another feature characterizing this invention the resilientreturn device acting upon said movable plate comprises an arm which, inthe normal position, extends horizontally to the rear in thelongitudinal direction of the ski and above said front jaw, said armcarrying a depending vertical pin extending through an aperture formedin said front jaw and through an elongated slot formed in said movableplate.

A few typical forms of embodiment of this invention will now bedescribed by way of example with reference to the attached drawing, inwhich:

FIG. 1 is a plane view from above illustrating a ski binding accordingto this invention, shown in its normal position; however, the rear endof the arm carried by said return device has been omitted to facilitatethe understanding of the drawing;

FIG. 2 is a similar view showing the maximum permissible lateralpivoting movement of the movable plate before the ski boot is released;

FIG. 3 is a similar view showing the plate position causing the fullrelease of the ski boot;

FIG. 4 is a longitudinal section taken along the line lVlV of FIG. 1;

FIG. 5 is a perspective exploded view showing the main componentelements of the binding of this invention;

FIG. 6 is a plane view from above showing a modified form of embodimentof this invention;

FIG. 7 is a sectional-elevational view of this modified form ofembodiment;

FIG. 8 is a cross section taken along the line VIII-VIII of FIG. 7; and

FIGS. 9 and 10 are plane views from above showing two different forms ofembodiment of the front jaw.

In the form of embodiment illustrated in FIGS. 1 to 5 inclusive the skibinding according to this invention comprises a movable plate 1extending along the top surface of the ski, throughout the length of thearea to be occupied by the ski boot C to be retained. At its rear end,this plate 1 is adapted to pivot about a fixed disc-shaped member 3constituting a bearing thereto. This member 3 secured to the top surfaceof the ski under the beel position acts at the same time as a bearing toa washer 2 carrying the heel holddown device for example of the typedescribed and illustrated in the U.S. Pat. No. 3,249,365.

This device may advantageously consist of a pivoting heel holddownmember 4 rotatably mounted about a horizontal pivot pin 5 carried by apair of lateral arms 6 pivotally mountedto a pair of cars 7 rigid withsaid rotary washer 2. The heel holddown member 4 is retained in itsnormal position by resilient means comprising a piston and springdevice. Now it may be noted that with this arrangement the member 4exerts a simple vertical thrust V on the heel, without any horizontalthrust I-I.

At its front end the movable plate 1 carries a jaw 8 adapted to beengaged by the toe end of the ski boot to be retained. This jaw isrotatably mounted on a vertical pivot pin 9 carried by the correspondingend of plate 1. Preferably, this pivot pin consists of a screw rodengaging a tapped hole of said jaw, so that the jaw can be adjusted inthe vertical direction.

Arranged in front of this jaw is a resilient return device acting bothupon the front end of the movable plate 1 and upon the front jaw 8. Thisreturn device must be so designed as to permit the sidewise movements ofthe plate 1 without allowing the jaw 8 to pivot before said plate 1 hasoverstepped the permissible or limit angle a so that this plate 1 can bereturned with the boot C to their nonnal position.

This resilient return device comprises an arm operatively connected withthe front end of the movable plate 1 and with the front jaw 8. This arm10 is carried by a case 20 adapted to rotate about a vertical pivot pin11 secured to the ski by means of a baseplate 12. This arm 8 and thecase 20 are held in and returned to their normal or central position bya resilient mechanism comprising a piston 13 slidably mounted in a boreof said case and responsive to a coil compression spring 14 constantlyurging said piston against a seat-forming flat face 15 formed on thepivot pin 11 and extending transversely to the longitudinal axis of theski.

Thus, this mechanism keeps the arm 10 in alignment with the longitudinalaxis of the ski. In this position, the arm 10 extends over the front jaw8. The rear end of arm 10 carries a vertical depending pin 16 extendingthrough an aperture 19 formed in the front jaw 8 and also through anelongated slot 17 formed in the front end portion of movable plate 1.This slot 17 extends over the longitudinal axis of plate 1 and its widthcorresponds to the diameter D of pin 16.

On the other hand, the aperture 19 formed in the jaw 8 has asubstantially Y-shaped configuration in plane view. In fact, itcomprises a longitudinal branch 21 extending to the rear and a pair ofdivergent front branches 22 extending obliquely on either side. As shownin the drawing, these two front branches correspond to circular arcshaving their center coincident with the axis of pivot pin 9 about whichthe jaw 8 is adapted to pivot. The width of the longitudinal branch 21of aperture 19 corresponds substantially to the diameter D of thecoupling pin 16 of arm 10.

It will be seen that in the normal position this pin 16 engages the rearend of the longitudinal branch 21 of aperture 19 formed in jaw 8. Ofcourse, this pin engages at the same time the rear end of thelongitudinal slot 17 formed in the front end of movable plate 1.

Under these conditions, the jaw 8 is prevented from pivoting about itspin 9, so that it will safely hold the toe end of the ski boot in thenormal skiing position, the heel of this boot being on the other handheld down by the retaining device provided at the heel end of the boot.

When a torque is exerted on the boot C, the abovedescribed ski bindingoperates as follows:

I. Case of a momentary torque The boot C can pivot bodily with themovable plate 1 through a maximum angle a (FIG. 2) without inasmuchbeing released from this plate. This pivotal movement is attended by arotational movement of arm 10 about its vertical pivot pin 11. As aresult, the spring 14 is compressed and exerts on the arm 10 a torque Murging this arm 10 backwards. Thus, when the initial torque ceases, thearm 10 of the return device restores the movable plate 1 and the skiersboot to their normal positions through the medium of the coupling pin 16which has slid in the longitudinal slot 17.

In this respect it may be noted that as long as the pivotal movementperformed by the boot and plate assembly does not exceed the angle a theboot remains stationary with respect to its supporting plate 1, so thatit is subsequently returned to its normal position with this plate. Thisis due to the fact that the coupling pin 16 simply slid in thelongitudinal branch 21 of the aperture 19 formed in jaw 8, so that thisjaw is constantly prevented from pivoting in relation to said plate 1.

Under these conditions, as long as the pivotal movement of boot C issmaller than said angle a, the device will automatically restore theboot to its normal position. Now, as can be seen in FIG. 2, this angle acorrespond to a relatively considerable pivotal movement of the boot.

It may also be noted that no frictional forces can interfere with thepivotal movement of the boot, in contrast to what is observed with mostski bindings wherein the ski boot engages directly the top surface ofthe ski. Besides, even if the boot received a forward thrust H from theheel holddown device, no detrimental influence would arise as far as theoperation of the toe retaining device is concerned.

2. Case of a prolonged torque In this case the boot C tends to pivotbeyond the limit angle a. When this angle is overstepped, the couplingpin 16 carried by the arm 10 is coincident with the intersection betweenthe longitudinal branch 21 of aperture 19 and its two oblique lateralbranches 22. Under these conditions, the jaw 8 can pivot in thedirection of the arrow F about its pivot pin 9 since the coupling pin 16can engage the corresponding lateral branch 22 of this aperture (seeFIG. 3).

The rotational movement of jaw 8 in relation to plate 1 will thus permitthe release of the toe end of the boot and therefore the completerelease of this boot from the ski S.

It should be noted that during this last step of the bootreleaseoperation the plate 1 remains in the position shown in FIG. 3, since itcannot continue its pivotal movement. However, the boot C can continuefreely its pivotal movement about the axis 0, since the heel can rotatebodily with the washer 2. Thus, in the position illustrated in FIG. 3,the boot C has pivoted through an angle )3 definitely greater than theangle a of the pivotal movement of plate 1.

Thus, the ski binding according to this invention operates somewhat intwo steps, thus affording a considerable prerelease swivel movement ofthe boot before the latter is actually released, with the certainty thatthe boot will be returned to its normal skiing position as long as thelimit angle a thus contemplated has not been overstepped by theswiveling boot.

Two facts appear clearly from the above description and the attacheddrawing:

a. the length of the longitudinal branch 21 of aperture 19 formed in thejaw 8 controls the magnitude of the permissible angular movement ofplate 1 which constitutes the limit stroke during which the jaw remainsstationary in relation to said plate 1;

b. the length of the longitudinal slot 17 formed in the front end ofsaid movable plate 1 controls the magnitude of the permissible angularmovement of this plate.

If desired, the two lengths mentioned in paragraphs (a) and (b)hereinabove may be equal, and in this case the two angular movementsinvolved are also equal. But the length of slot 17 may also be greaterthan that of the longitudinal branch 21 of aperture 19, and in this casethe movable plate 1 will continue its pivotal movement after the jaw 8itself has begun its inherent pivoting movement in relation to thisplate.

Preferably, the ski binding according to this invention is constructedwith a view to prevent its normal operation from being disturbed by apossible bending of the ski, for example when skiing on a concavesurface. To this end, a play e is provided on purpose between the frontend 18 of plate 1 and the baseplate 12 for mounting the resilient returndevice. A same play e may also be provided between the coupling pin 16and the rear ends of aperture 19 and longitudinal slot 17.

FIGS. 6, 7 and 8 illustrate a modified form of embodiment of theinvention wherein the movable plate 1a of this binding is separated fromthe heel holddown device. In this form of embodiment the rear end ofplate 1a is pivoted about the center 0, of a disc-shaped stationarymember 24 acting as a bearing. This center 0, is substantiallycoincident with the axis of the skiers leg.

This member is thus disposed ahead of the heel position. Underlying thisheel position is a plate 25 carried by the ski and mounted for freerotation about a vertical axis 26. This plate 25 is adapted to support aheel holddown device 4, 5 for example of same type as the devicecontemplated in the preceding form of embodiment.

To reduce the frictional contact between the ski and the front end 18aof movable plate In, this plate la carries a bearing memberadvantageously consisting of a roller 27 rolling on a track-formingblade or plate 28 secured to the top surface of the ski and rigid withthe baseplate 12a provided for securing the resilient return device.

Since the ski boot sole abuts against the. front jaw 8 in the directionshown by the arrow A, the resulting thrust exerts on the plate In atorque causing the roller 27 to exert in turn a pressure V. on the blade28 and also a force V tending to lift the portion 29 of plate la of theski top. This last-mentioned force will thus counteract the pressureexerted upon the plate 1a by the skiers weight, so that the frictionalcontact between this plate and the ski is reduced considerably.

As clearly seen in FIGS. 7 and 8, the diameter D of the coupling pin 16of the resilient return device is greater above the front end 18a ofplate la than the diameter D, of the lower portion of this coupling pinwhich engages the longitudinal slot 17.

As a result, a shoulder 30 assisting in holding the front end of platela against the ski surface is formed.

FIGS. 9 and are detail views showing modified forms of embodiment of thefront jaw carried by the movable plate 1 of this invention. In thesealternate forms of embodiment 8a and 8b the longitudinal branch 21a or21b of aperture 19a or 19b formed in said jaw flares out forwards at itsintersection with the lateral oblique branches 22a and 22b. This widenedjunction is useful in case the pivot centers 0, and 26 of the movableplate 1a and of the boot heel are not coincident, in contrast to thearrangement of the first form of embodiment illustrated in FIGS. 1 to 5.

As clearly shown in the drawing the front jaw 8 of this invention isadapted to coact with the comers of the toe end of the ski boot sole. Infact, this jaw is formed with lateral ledges 31 disposed on either sideof. the toe corners of the sole. Besides, this jaw comprises ahorizontal upper shoulder 32 adapted to fit on the top of the toe edgeof the sole for urging same against the ski.

However, this ski binding may also comprise a front jaw adapted to coactwith the rounded toe end of the boot upper, in lieu of with the bootsole.

Besides, in case the movable plate la were pivoted to thebearing-forming plate 24, the former may comprise a rear extension asshown in dash and dot lines at lb. Thus, a heel holddown device of anysuitable type may be mounted on this extension, for example in a mannerpermitting its longitudinal movement for accommodating different bootlengths.

In the various forms of embodiment described hereinabove it appears thatthe main advantage characterizing the ski binding of this invention isthat a relatively long swivel movement of the toe end of the boot cantake place before it is eventually released. Another advantageousfeature characterizing this device is that its operation is independentof the horizontal thrust H likely to be exerted by the heel holddowndevice. In any case the thrusts H or A are transmitted only to the frontjaw 8, not to the resilient return device. Under these conditions, thisresilient return device is not exposed to considerable stresses but onlyto the return torque M.

Of course, this safety ski binding should not be construed as beingstrictly limited by the specific forms of embodiment described andillustrated herein.

Besides, this ski binding may be associated with any desired andsuitable device intended for holding down or retaining the heel portionof the ski boot.

What I claim is:

l. A safety ski binding for controlling movement of a ski bootcomprising a movable plate for carrying at least a portion of the bootthereon, means for pivotally mounting said plate about a firstsubstantially vertical axis on a ski, a jaw member pivotally mountedabout a second substantially vertical axis on said movable plate facingthe ski boot, said jaw member normally retaining said boot againstlateral movement with respect to said ski, means mounted on said ski forexerting a return force on said movable plate comprising an arm, saidarm also being mounted on said jaw member, said arm also maintainingsaid jaw member in a predetermined alignment with respect to saidmovable plate until said movable plate has pivoted to a predeterminedangle, said arm permitting pivotal motion of said jaw member withrespect to said plate to release the boot from the binding after saidpredetermined angle has been reached.

2. A safety binding as specified in claim 1 wherein said arm ispivotable with said movable plate, said arm applying a return force tosaid movable plate as said plate moves.

3. A safety binding as specified in claim 1 wherein said arm ispivotable with said movable plate, the distance between the point atwhich said arm pivots and the point at which said arm applies a returnforce to said jaw member remaining constant.

4. A safety binding as specified in claim 1 further comprising acompression spring mounted on said arm, said spring being compressed assaid movable plate pivots to apply a return force to said movable plate.

5. A safety binding as specified in claim 1 wherein said arm has a pindepending therefrom, said jaw member having a slot therein adapted toreceive said depending pin, said slot having a first extension lyingover the longitudinal axis of said movable plate when said jaw member ismaintained in alignment with said movable plate and a second arcuateextension into which said depending pin moves when said movable platehas pivoted to said predetermined angle, a slot in said movable plateunderlying the longitudinal slot in said jaw member, said depending pinalso engaging the slot in the movable plate, said arm beingnonextensible whereby during pivotal motion of said movable plate, saiddepending pin will move along the slot in said movable plate and alongthe longitudinal slot in said jaw member until the depending pin ispositioned in said arcuate slot whereupon said jaw member may pivot onsaid movable plate.

6. A safety release binding for a ski boot, comprising a movable platefor carrying at least a portion of the ski boot thereon, means forpivotally mounting said plate to the ski, a jaw member pivotally mountedon said movable plate in front of the boot and retaining said bootagainst lateral and forward movement with respect to said movable plateduring a first angular movement of said movable plate with respect tothe ski a resilient return device mounted on the ski in front of saidmovable plate and operatively connected both to the jaw member and tothe movable plate for controlling relative movement between said movableplate and said jaw member as well as between said movable plate and theski, a vertical control pin mounted on the return device, a first slotextending longitudinally in the jaw member and a second slot extendinglongitudinally in the movable plate, said control pin engaging bothslots, said first slot being enlarged at one end to permit angularmovement of the jaw member with respect to the movable plate after thefirst angular movement of the plate with respect to the ski.

7. The safety release binding specified in claim 6 wherein said controlpin has a diameter somewhat less than the minimum dimension of saidfirst and second slots to permit free movement of said control pin insaid slots.

8. The safety device specified in claim 7 wherein said first slot isenlarged in a semicircular path.

9. The safety device specified in claim 6 wherein the width of the firstslot is greater than the width of said second slot, said control pinhaving a larger diameter in the region of engagement with the first slotto form a holddown shoulder for said movable plate, said holddownshoulder controlling upward movement of said movable plate.

10. The safety device specified in claim 6 wherein said resilient returndevice comprises an arm mounted for rotation on a semicircular pin, saidarm being hollow at least to one side of said pin and containing aspring therein, a piston on one end of said spring, said piston bearingagainst the other end of said spring, said pin in the region ofnoncircularity of said pin bearing against one end of said arm, said pincompressing said spring as said arm rotates in response to outwardpivoting movement of said movable plate.

11. The safety device specified in claim 6 wherein the longitudinalportions of the first slot and the second slot are aligned one over theother when said movable plate is pivoted less than a predeterminedamount, said pin being adapted to move into the enlarged region of saidfirst slot after said movable plate has pivoted past a predeterminedangle, said longituresilient return device is mounted on a supportingplate, said bearing member riding on said supporting plate.

14. The safety device specified in claim 13 wherein said bearing memberis a roller.

1. A safety ski binding for controlling movement of a ski bootcomprising a movable plate for carrying at least a portion of the bootthereon, means for pivotally mounting said plate about a firstsubstantially vertical axis on a ski, a jaw member pivotally mountedabout a second substantially vertical axis on said movable plate facingthe ski boot, said jaw member normally retaining said boot againstlateral movement with respect to said ski, means mounted on said ski forexerting a return force on said movable plate comprising an arm, saidarm also being mounted on said jaw member, said arm also maintainingsaid jaw member in a predetermined alignment with respect to saidmovable plate until said movable plate has pivoted to a predeterminedangle, said arm permitting pivotal motion of said jaw member withrespect to said plate to release the boot from the binding after saidpredetermined angle has been reached.
 2. A safety binding as specifiedin claim 1 wherein said arm is pivotable with said movable plate, saidarm applying a return force to said movable plate as said plate moves.3. A safety binding as specified in claim 1 wherein said arm ispivotable with said movable plate, the distance between the point atwhich said arm pivots and the point at which said arm applies a returnforce to said jaw member remaining constant.
 4. A safety binding asspecified in claim 1 further comprising a compression spring mounted onsaid arm, said spring being compressed as said movable plate pivots toapply a return force to said movable plate.
 5. A safety binding asspecified in claim 1 wherein said arm has a pin depending therefrom,said jaw member having a slot therein adapted to receive said dependingpin, said slot having a first extension lying over the longitudinal axisof said movable plate when said jaw member is maintained in alignmentwith said movable plate and a second arcuate extension into which saiddepending pin moves when said movable plate has pivoted to saidpredetermined angle, a slot in said movable plate underlying thelongitudinal slot in said jaw member, said depending pin also engagingthe slot in the movable plate, said arm being nonextensible wherebyduring pivotal motion of said movable plate, said depending pin willmove along the slot in said movable plate and along the longitudinalslot in said jaw member until the depending pin is positioned in saidarcuate slot whereupon said jaw member may pivot On said movable plate.6. A safety release binding for a ski boot, comprising a movable platefor carrying at least a portion of the ski boot thereon, means forpivotally mounting said plate to the ski, a jaw member pivotally mountedon said movable plate in front of the boot and retaining said bootagainst lateral and forward movement with respect to said movable plateduring a first angular movement of said movable plate with respect tothe ski, a resilient return device mounted on the ski in front of saidmovable plate and operatively connected both to the jaw member and tothe movable plate for controlling relative movement between said movableplate and said jaw member as well as between said movable plate and theski, a vertical control pin mounted on the return device, a first slotextending longitudinally in the jaw member and a second slot extendinglongitudinally in the movable plate, said control pin engaging bothslots, said first slot being enlarged at one end to permit angularmovement of the jaw member with respect to the movable plate after thefirst angular movement of the plate with respect to the ski.
 7. Thesafety release binding specified in claim 6 wherein said control pin hasa diameter somewhat less than the minimum dimension of said first andsecond slots to permit free movement of said control pin in said slots.8. The safety device specified in claim 7 wherein said first slot isenlarged in a semicircular path.
 9. The safety device specified in claim6 wherein the width of the first slot is greater than the width of saidsecond slot, said control pin having a larger diameter in the region ofengagement with the first slot to form a holddown shoulder for saidmovable plate, said holddown shoulder controlling upward movement ofsaid movable plate.
 10. The safety device specified in claim 6 whereinsaid resilient return device comprises an arm mounted for rotation on asemicircular pin, said arm being hollow at least to one side of said pinand containing a spring therein, a piston on one end of said spring,said piston bearing against the other end of said spring, said pin inthe region of noncircularity of said pin bearing against one end of saidarm, said pin compressing said spring as said arm rotates in response tooutward pivoting movement of said movable plate.
 11. The safety devicespecified in claim 6 wherein the longitudinal portions of the first slotand the second slot are aligned one over the other when said movableplate is pivoted less than a predetermined amount, said pin beingadapted to move into the enlarged region of said first slot after saidmovable plate has pivoted past a predetermined angle, said longitudinalportion and said second slot being out of alignment after said movableplate has pivoted past said predetermined angle.
 12. The safety devicespecified in claim 6 further comprising a bearing member mounted on saidmovable plate, for reducing friction between said ski and said movableplate.
 13. The safety device specified in claim 12 wherein saidresilient return device is mounted on a supporting plate, said bearingmember riding on said supporting plate.
 14. The safety device specifiedin claim 13 wherein said bearing member is a roller.